Fatty liver refers to a pathogenic condition where fat comprises more than 5% of the total weight of the liver. Liver diseases including the fatty liver, hepatitis, fibrosis and cirrhosis are known to be the most serious disease next to cancer causing death in people with ages 40 to 50, in the advanced countries. In advanced countries, nearly about 30% of the population is with fatty liver, and about 20% of people with fatty liver progresses to cirrhosis. About half of the cirrhosis patients die of liver diseases within 10 years after the diagnosis. Fatty liver and steatohepatitis are frequently found in people who intake excessive alcohols and who have obesity, diabetes, hyperlipemia, etc. Among them, alcoholic steatohepatitis (ASH), which is caused by excessive alcohol intake, is at high risk of progressing to hepatitis, cirrhosis and hepatoma, along with non-alcoholic steatohepatitis (NASH).
When taken in, alcohol is carried to the liver and oxidized to acetaldehyde by such enzymes as alcohol dehydrogenase, catalase, etc. The acetaldehyde is metabolized and converted into acetate and is used as energy source. Repeated alcohol intake induces the increase of NADH and NADP+ during the metabolism and acetaldehyde which as the metabolite product of alcohol depletes GSH, thereby changing intracellular oxidation-reduction homeostasis and inducing oxidative stress. Oxidative stress may cause mitochondrial dysfunction, lipid peroxidation and protein modification, thereby leading to death of hepatocytes, inflammation, activation of astrocytes, and the like. In addition, the increase of NADH promotes lipid synthesis, thereby inducing fatty liver.
At present, there are few therapeutically effective drugs for treating fatty liver. Exercise and controlled diet are recommended, but these are not so effective in treating fatty liver. The development of an effective treatment drug is in desperate need. As it is known that fatty liver is related with insulin resistance which is found in diabetes and obesity, the therapeutic effect of some anti-diabetic drugs, e.g., metformin, on fatty liver has been reported. But, the drug has the problem that it may induce adverse reactions such as hepatotoxicity or lactic acidosis. Betaine, glucuronate, methionine, choline and lipotrophic agents are often used as alternative supplementary drug therapy, but they are not fully proven on medical or pharmaceutical basis. Accordingly, development of a fatty liver treatment having superior effect and safety with no adverse reactions is in need.
Metadoxine (pyridoxol 1-2-pyrrolidone-5-carboxylate) is a complex compound of pyridoxine and pyrrolidone carboxylate represented by the formula (1) below:

Metadoxine is a drug used to treat alcoholic liver disease. It is used to treat liver fibrosis and fatty liver through increasing alcohol metabolism and turnover, reducing toxicity of free radicals and restoring the level of ATP and glutathione (Arosio, et al., Pharmacol. Toxicol. 73: 301-304, 1993; Calabrese, et al., Int. J. Tissue React. 17: 101-108, 1995; Calabrese, et al., Drugs Exp. Clin. Res. 24: 85-91, 1998; Caballeria, et al., J. Hepatol. 28: 54-60, 1998; and Muriel, et al., Liver Int. 23: 262-268, 2003).
However, metadoxine is unable to inhibit the expression and activation of alcohol-induced cytochrome P4502E1 (CYP2E1), which is a key enzyme involved in alcohol-induced toxicity, and thus unable to control the augmentation of inflammation mediated by CYP2E1. Therefore, the treatment of alcohol-induced fatty liver using metadoxine is very limited. Further, the expression of CYP2E1 is related with insulin resistance, thus metadoxine cannot not overcome insulin resistance.
Garlic oil is a liquid including about 1% of allicin along with reduced allicin and other sulfur-containing substances. Upon binding to vitamin B1, allicin is turned into allithiamin, which is chemically stable, acts swiftly, and is easily absorbed by the digestive organs. The substance inhibits carcinogenesis induced by chemicals in white rats (Brady, et al., Cancer Res. 48: 5937-5940, 1988; and Reddy, et al., Cancer Res. 53: 3493-3498, 1993), induces phase II enzyme (Hayes, et al., Carcinogenesis 8: 1155-1157, 1987; and Sparnins, et al., Carcinogenesis 9: 131-134, 1988), and inactivates CYP2E1 (Brady, et al., Chem. Res. Toxicol. 4:642-647, 1991). In addition, garlic oil is reported to have antithrombotic, anti-atherosclerotic, antimutagenic, anticancer and antibacterial activities (Agarwal, Med. Res. Rev. 16: 111-124, 1996; and Augusti, Indian J. Exp. Biol. 34: 634-660, 1996).